PASCAGOULA — State environmental agencies warned fishermen Monday not to eat fish caught in or near industrial Bayou Casotte in east Pascagoula until they have time to find out what’s killing them.

Thousands of fish of different varieties were reported dead and floating in the bayou on Sunday. And on Monday, two biologists were taking water and animal samples to see what killed them.

It could be an industrial accident or natural causes in the wake of the hurricane, said Earl Etheridge, coordinator of the state’s environmental emergency response team. The Mississippi departments of Environmental Quality and Marine Resources are double-teaming the event.

“But it doesn’t seem to be affecting the birds,” he said. Hundreds of birds have been eating the floating fish and making a substantial dent in the mess, he said.

Bayou Casotte, home to chemical plants and other industry, is a large body of “pretty slow-moving water,” he said.

The state departments closed the bayou Sunday to all fishing and water contact and the Mississippi Sound within 1,000 feet of the mouth of the bayou.

The public is advised to avoid these waters and while seafood is not considered to be contaminated, fishermen are advised not to consume any seafood collected from these waters until further notice.

This precautionary closure was issued to protect the public from potentially harmful water conditions and does not affect navigation interests, the agencies said.

“Biologists are out there counting dead fish and surveying the bayou and doing water quality samples,” Etheridge said. “We’re not sure what it is.”

They are sampling the nearby Bangs Lake area as well.

“If it’s natural, it could have been stress from the mud kicked up and low oxygen levels in the water, brought on by the hurricane,” he said. “This is one of those things where you have to wait for the science to determine what it is.”